About 3:13 is where the tune starts, and although I don't know the tune, it's amazing, that background-chord + Melody trick Howard does at 3:32ish... Mindblowing to see/hear live, I'd never experienced that before.

Sounds like a classic irish ballad, almost? I've heard it so many places but never knew the tune :'(

Hey I know it!!! All those years of classical training are finally paying off! It's "Jesu, Joy of Man's Desiring" by the incredible Johann Sebastian Bach! You'll find a ton of versions out there on a ton of different instruments, it's a "classic"... hahaha. And, he played that at the concert I attended last summer too, it was mind-blowing!!!